The present invention relates to a novel process for preparing a stable silicone oil containing xe2x89xa1SiH groups and hydrosilylable functions. In particular, the invention relates to a process of hydrosilylation between silicone oils containing xe2x89xa1SiH groups and monomers with two hydrosilylable units.
Reactions of silicone oils containing xe2x89xa1SiH groups with olefins or acetylenic hydrocarbons are very well known. The silicone oils are, for example, of the formulae:
xe2x80x94Me3SiOxe2x80x94(MeHSiO)nxe2x80x94(Me2SiO)mxe2x80x94SiMe3 
in which n and m are integers or fractions such that 1xe2x89xa6nxe2x89xa61000 and 0xe2x89xa6mxe2x89xa61000;
xe2x80x94Me2HSiOxe2x80x94(MeHSiO)oxe2x80x94(Me2SiO)pxe2x80x94SiHMe2 
in which o and p are integers or fractions such that 0xe2x89xa6oxe2x89xa61000 and 0xe2x89xa6pxe2x89xa61000.
Many monomers can functionalize silicone oils; for example, alkenes, styrenes, allyl alcohols, allyloxy ethers or allylamines are used as monomers.
These reactions are very commonly used for the synthesis of functionalized silicone oils starting with silicone oils containing xe2x89xa1SiH groups, which, during the hydrosilylation reaction, are functionalized by the monomers. The oils obtained, containing virtually no xe2x89xa1SiH units, have applications in very wide fields such as anti-adhesion and lubrication.
In particular, functionalized oils can be prepared with 1,2-epoxy-4-vinylcyclohexane monomers. By way of application, these functionalized silicone oils are then thermally crosslinked in the presence of an acid catalyst such as hydrochloric acid or sulphuric acid, or photochemically crosslinked in the presence, for example, of a cationic photo-initiator for the preparation of anti-adhesive films for paper and/or plastics.
A very large number of catalytic compositions is used in hydrosilylation reactions. The catalytic compositions most widely known contain metals such as platinum, rhodium, cobalt or palladium. Specific examples of such catalytic compositions are platinum halides and rhodium halides, for example H2PtCl6, PtCl2, (RhCl3.H2O), complexes of platinum with siloxanes containing unsaturated groups, complexes of platinum with olefins and cationic complexes of platinum with nitrites as ligands.
Generally, the catalytic compositions used in the hydrosilylation reaction are homogeneous catalytic compositions, i.e. the said compositions are dissolved in the reaction medium. One of the compositions most widely used is the catalytic Karstedt composition described in particular in U.S. Pat. No. 3,775,452.
However, during the hydrosilylation reaction according to processes of the prior art, isomerization reactions of the unsaturated monomers are observed to different degrees, which makes it necessary to work with a molar excess of monomer relative to the silicone oil in the reaction medium.
Moreover, when it is desired to prepare silicone oils comprising both xe2x89xa1SiH groups and hydrosilylable functions in the structure, the processes of the prior art are inapplicable and unsuitable; the silicone oils obtained are not stable to allow their subsequent use. In particular, during the devolatilization step, the hydrosilylable functions grafted onto the silicone oil structure have a tendency to react together, as in the case of the totally functionalized silicone oils, and/or with the xe2x89xa1SiH groups of the silicone oil obtained; this gives rise to uncontrolled polymerization and crosslinking reactions and is reflected in the formation of gum and/or resin. These reactions can be initiated in particular by the presence of a trace of the usual catalytic compositions, such as homogeneous catalytic compositions.
In addition, the functionalized silicone oils obtained from processes using homogeneous catalysis are generally colored, from about 80 to about 300 Hazen; consequently, this limits the fields in which it can be envisaged to use them, in particular in transparent and anti-adhesive films for paper or for transparent films (for example of polyester type). In these cases, the silicone oil requires additional purification steps in order to be usable after crosslinking, in transparent films; these additional steps make the industrial implementation expensive and thus economically relatively non-viable.
The Applicant has developed a novel process for preparing a stable silicone oil, containing both xe2x89xa1SiH groups and hydrosilylable functions, and which allows the drawbacks mentioned above to be reduced significantly, in particular the uncontrolled reactions during the devolatilization step.
This novel process for preparing a stable silicone oil containing xe2x89xa1SiH groups and hydrosilylable functions is carried out using a first silicone oil containing xe2x89xa1SiH groups and monomers with two hydrosilylable units.
The silicone oils obtained from the process according to the invention comprise both xe2x89xa1SiH groups and hydrosilylable functions and are stable during the devolatilization step and stable on storage; this makes it possible subsequently to use the silicone oils according to the invention in applications which require both the presence of xe2x89xa1SiH groups and hydrosilylable monomers.
In addition, the process according to the invention makes it possible to obtain colorless and transparent oils, with a very low coloration from about 3 to about 100 Hazen, without requiring decolorization and/or purification steps which are relatively non-viable economically and industrially. Needless to say, it is necessary, for this purpose, for the starting monomers to be colorless and transparent.
In particular, the silicone oils obtained from the process of the invention can be used, after crosslinking, in transparent and anti-adhesive films and coatings for papers, for glasses and for plastics.
This novel process for preparing a stable silicone oil containing xe2x89xa1SiH groups and hydrosilylable functions from a starting oil, referred to as the first silicone oil, containing xe2x89xa1SiH groups and monomers with two hydrosilylable units, comprises the following steps:
(a) an amount of from 5 to 5000 ppm, preferably from 10 to 100 ppm, of heterogeneous catalytic composition relative to the total mass of the reagents is introduced into the reaction medium;
(b) the first silicone oil is introduced into the reaction medium;
(c) the said reaction medium is heated to a temperature of between 25xc2x0 C. and 200xc2x0 C. and preferably between 50xc2x0 C. and 160xc2x0 C.;
(d) the monomers are then introduced over a period of between 0 and 24 h, preferably between 2.5 and 5 h; the monomer/xe2x89xa1SiH molar ratio of the said oil is between 0.0001 and 1;
(e) the silicone oil obtained containing xe2x89xa1SiH groups and hydrosilylable functions is then separated from the heterogeneous catalytic composition, for example by filtration; and
(f) the silicone oil containing xe2x89xa1SiH groups and hydrosilylable functions is finally devolatilized.
The separation step (e) makes it possible, where appropriate, to remove all trace of turbidity from the functionalized silicone oil obtained. Moreover, the heterogeneous catalytic composition can be recovered and then reused, without the need for regeneration, with or without washing, and without any appreciable reduction in its performance characteristics being detected. As regards the devolatilization (f), the stability of the silicone oils is not affected during this step.
Furthermore, the process according to the invention can advantageously be carried out in bulk, which means that the reaction between the silicone oil and the monomer(s) is carried out in the absence of solvent. However, many solvents such as toluene, xylene, octamethyltetrasiloxane, cyclohexane or hexane can be used.
Virtually any type of monomer containing two hydrosilylable units can be used in the present process. Furthermore, the monomers used can be identical and/or different. However, preferably, at least one of the hydrosilylable units of the monomers is a vinyl or allylic unit.
The best results for the preparation of silicone oils, in accordance with the spirit of the invention, were obtained with monomers having the formulae: 
in which:
the symbols R1 and R2, which may be identical and/or different, correspond to a monovalent hydrocarbon-based radical chosen from a phenyl radical and linear or branched alkyl radicals containing from 1 to 12 carbon atoms, preferably a hydrogen atom or a methyl radical;
the symbol Y corresponds to Yxe2x80x2-Yxe2x80x3-Yxe2x80x2 in which:
the symbol Yxe2x80x3 corresponds to a divalent radical chosen from xe2x80x94(Cxe2x95x90O)xe2x80x94, xe2x80x94(NH)xe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94(Cxe2x95x90O)xe2x80x94Oxe2x80x94, xe2x80x94NHxe2x80x94(Cxe2x95x90O)xe2x80x94 and a free valency,
the symbols Yxe2x80x2, which may be identical and/or different, correspond to a divalent hydrocarbon-based radical chosen from linear or branched alkyl radicals containing from 1 to 6 carbon atoms and a free valency, it being possible for one of the radicals Yxe2x80x2 to be a phenyl radical or an alkylaryl radical in which the linear or branched alkyl part comprises 1 to 6 carbon atoms. 
in which:
the symbol Z corresponds to a monovalent radical xe2x80x94NHR4 or OH,
the symbols R3 and R4, which may be identical and/or different, correspond to a monovalent hydrocarbon-based radical chosen from a phenyl radical and linear or branched alkyl radicals containing from 1 to 12 carbon atoms; and preferably a hydrogen atom or a methyl radical,
the symbol Y corresponds to Yxe2x80x2-Yxe2x80x3-Yxe2x80x2, in which:
the symbol Yxe2x80x3 corresponds to a divalent radical chosen from xe2x80x94(Cxe2x95x90O)xe2x80x94, xe2x80x94(NH)xe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94(Cxe2x95x90O)xe2x80x94Oxe2x80x94, xe2x80x94NHxe2x80x94(Cxe2x95x90O)xe2x80x94 and a free valency,
the symbols Yxe2x80x2, which may be identical and/or different, correspond to a divalent hydrocarbon-based radical chosen from linear or branched alkyl radicals containing from 1 to 6 carbon atoms, and a free valency, it being possible for one of the radicals Yxe2x80x2 to be a phenyl radical or an alkylaryl radical in which the linear or branched alkyl part comprises 1 to 6 carbon atoms, 
in which:
the symbol U corresponds to a divalent radical chosen from xe2x80x94NHxe2x80x94, xe2x80x94(Cxe2x95x90O)xe2x80x94, xe2x80x94(Cxe2x95x90O)xe2x80x94NHxe2x80x94, and xe2x80x94(Cxe2x95x90O)xe2x80x94Oxe2x80x94(Cxe2x95x90O)xe2x80x94,
the symbol R5 corresponds to a monovalent hydrocarbon-based radical chosen from a phenyl radical and linear or branched alkyl radicals containing from 1 to 12 carbon atoms, preferably a hydrogen atom or a methyl radical;
the symbols W1 and W2, which may be identical and/or different, correspond to a divalent hydrocarbon-based radical chosen from a phenyl radical, linear or branched alkyl radicals containing from 1 to 12 carbon atoms, alkylaryl radicals in which the linear or branched alkyl part comprises 1 to 6 carbon atoms, and a free valency,
the symbol Y corresponds to Yxe2x80x2-Yxe2x80x3,-Yxe2x80x2, in which:
the symbol Yxe2x80x3 corresponds to a divalent radical chosen from xe2x80x94(Cxe2x95x90O)xe2x80x94, xe2x80x94(NH)xe2x80x94, xe2x80x94Oxe2x80x94, xe2x80x94(Cxe2x95x90O)xe2x80x94Oxe2x80x94, xe2x80x94NHxe2x80x94(Cxe2x95x90O)xe2x80x94, and a free valency,
the symbols Yxe2x80x2, which may be identical and/or different, correspond to a divalent hydrocarbon-based radical chosen from linear or branched alkyl radicals containing from 1 to 6 carbon atoms, and a free valency, it being possible for one of the radicals Yxe2x80x2 to be a phenyl radical or an alkylaryl radical in which the linear or branched alkyl part comprises 1 to 6 carbon atoms.
According to a preferred embodiment of the process according to the invention, the monomers used to prepare the silicones according to the invention are monomers in which one of the hydrosilylable units is a vinyl or allylic unit and contains at least one hydrocarbon-based ring in which at least one oxygen atom is included.
Mention will be made in particular of the monomers of formulae: 
According to another preferred embodiment of the process according to the invention, the monomers used to prepare the silicones according to the invention are monomers in which one of the hydrosilylable units is a vinyl or allylic unit and contains at least one hydrocarbon-based ring in which a nitrogen atom forming a stearically hindered amine is included. These stearically hindered amines can advantageously be of HALS type, for example, of formula: 
Besides the monomers cited as preference, other types of monomer can be used, for example, in a non-limiting manner: 
When the monomers contain a hydrosilylable function in the form of a ring containing an oxygen atom, for example 1,2-epoxy-4-vinylcyclohexane [formula (IV)], it is noted that the use of the novel process for preparing stable silicone oils containing both xe2x89xa1SiH groups and hydrosilylable functions of this type makes it possible to significantly reduce the isomerization reactions of the unsaturated monomer and, furthermore, to substantially reduce the opening of the ring containing an oxygen atom present on the unsaturated monomer during the hydrosilylation and during the devolatilization step.
Thus, according to the process of the invention, silicone oils which are very stable over time, containing both xe2x89xa1SiH groups and hydrosilylable functions (epoxy, vinyl, etc.) are obtained, which makes it possible to use them in applications requiring, firstly, stability of the silicone oils, i.e. the unreactivity of the xe2x89xa1SiH groups and of the hydrosilylable functions, and, secondly, during their use, the reactivity (for example: crosslinking) of the hydrosilylable functions with each other and, simultaneously or otherwise, the reactivity of the said hydrosilylable functions with the xe2x89xa1SiH groups.
In accordance with the process according to the invention, the starting oils, also referred to as first oils in the context of the disclosure of the invention, are of diverse nature. They are either linear or cyclic and have the average formulae (VII) and/or (VIII): 
in which:
the symbols R6 are identical or different and correspond to a monovalent hydrocarbon-based radical chosen from a phenyl radical and linear or branched alkyl radicals containing from 1 to 6 carbon atoms;
the symbols X are identical or different and correspond to a monovalent radical chosen from R6, a hydrogen atom, a methoxy radical and an ethoxy radical;
a, b and c are integers or fractions such that;
0 less than axe2x89xa61000, preferably 0 less than axe2x89xa6100,
0xe2x89xa6b+cxe2x89xa6200, preferably 1 less than b+cxe2x89xa6100, and at least one of the two groups X corresponds to a hydrogen radical if b+c=0,
1 less than a+b+cxe2x89xa61000, preferably 1 less than a+b+cxe2x89xa6100;
d, e and f are integers or fractions such that:
0 less than d less than 10, preferably 0 less than d less than 5
1 less than e+f less than 10, preferably 1 less than e+f less than 5.
The silicone oils obtained are, respectively, silicone oils of formula (IX) and (X): 
in which:
the symbols R6, which may be identical or different, have the same meanings as above,
the symbols X, which may be identical or different, correspond to M and/or have the same meanings as above and at least one of the two groups X corresponds to M if b=0,
the symbols M, which may be identical or different, represent hydrosilylable units which is derived from the monomers described above,
a, b, c, d, e and f have the same meanings as described above, and:
0xe2x89xa6bxe2x89xa6200,
1 less than e less than 9.
In the context of the invention, various types of heterogeneous catalytic composition can be used. The heterogeneous catalytic composition used comprises at least one metal chosen from the group consisting of cobalt, rhodium, ruthenium, platinum and nickel, deposited on an inert support, the metal preferably being platinum. The inert support is selected from the group consisting of carbon black, charcoal, xcex1-alumina, silica, barium silicate and barium sulphate, the inert support preferably being carbon black. The amount of metal in the catalytic composition is advantageously between 0.1% and 5% relative to the weight of the inert support. In addition, this amount of metal in the catalytic composition is such that it is between 1 and 1000 ppm relative to the weight of the silicone oil.
Platinum on carbon black or charcoal, such as the catalytic composition containing 2.5% platinum by weight deposited on the support CECA 2S developed by the company CECA, the catalytic composition SCAT 20 (1% Pt) from the company Engelhard or the catalytic composition 88 231 (1% Pt) from the company Heraeus can be used, as non-limiting examples of catalytic compositions. In this case, the platinum can be deposited on this type of support by deposition of chloroplatinic acid followed by neutrilization and reduction. Similarly, the use of platinum on alumina preferably of xcex1 type, such as the catalytic composition CAL 101 (0.3% Pt, SCS9 support consisting of xcex1-alumina) sold by the company Procatalyse or the catalytic composition 88 823 from the company Heraeus (0.5% Pt on xcex1-alumina), gives good results. Furthermore, other catalytic compositions from the company Engelhard are appropriate for use in the process according to the invention: the catalyst 8006 (5% Rh/carbon black); the catalyst 7025 (3% Pt/carbon black) and the catalyst 40968 (1% Pt/granular charcoal).
The process according to the invention can be carried out according to many variants. In particular, it is possible to use a first implementation in which all of the reagents and the catalytic composition are mixed together in the reaction medium (xe2x80x9cbatchxe2x80x9d type). As a second embodiment of the process according to the invention, this process can be carried out continuously with a fixed bed of heterogeneous catalytic composition over or through which the silicone oil to be functionalized and the monomer(s) pass. This type of implementation is particularly advantageous when the grain size of the inert support for the catalytic composition is greater than 100 xcexcm.